Signaling system



June 15 1926.

H. W. ONEILL SIGNALING SYSTEM hkenfgn- Hep/y W OIVeI/Z June 15 1926.

f H; w. ONEILL SIGNALING SYSTEM Filed Nov. 27,

2 Shets-Sheet 2 lm/enfor. Hen/y W07ve/7/ H NN H @w w V. 8 a W Qw Patented June, 15, 1926.

UNITED STATES PATENT OFFICE.

HENRY V7. ONEILL, F BROOKLYN, NEW YORK, ASSIGNOI TO WESTERN ELECTRIC' COMPANY, INCORPORATED, OF NEW.YORK, N. Y., A CORPORATION OF NEW YORK.

SIGNALING SYSTEM.

This invention relates to signaling systems and more particularly to improved methods and means for signaling over transmission lines. y

In such systems as'are mentioned above, it not unusual that considerable interference with telephone apparatus caused by the operation of associated telegraph devices and by inductive surges from neighboring power transmission lines is encountered. In some signaling systems wherein current impulses are utilized to transmit "IIIGSSEtgQS, a considerable factor of error may be present without materially detracting from the successful operation of the system. However, in automatic telephony, wherein current impulses are employed to operate selective mechanisms to establish telephonic connections, it is necessary that substantially one hundred per cent of they impulses trans-- mitted be effective in operating the auto matic switching apparatus in order to prevent false connections being set up.

lnan automatic telephone system, let it be assumed that a set of 5, 7 and 9 current impulses are required to seize a certain line switch. If during the dialing of these impulses, the transmission line experiences an inductive surge caused by a neighboringline Gilly the operation of its own associated telegraph apparatus, the operating impulses may be distorted and mutilated to such an extent as to cause the false operation of telephone apparatus on the line and would possibly seize a switch other than the one originally intended for seizure, thereby setting up a false connection.

it is, therefore, an object of this invention to prevent the false operation of apparatus on a transmission line due to inductive surges.

A further object of this invention is to produce a. signal indicating an unstandard condition on a transmission line.

In accordance with the above and other objects, this invention provides an electricall -q symmetrical circuit which under ab normal conditions and at any time during the period of sending of impulses, is adapted to operate a signal at the sending point.

Further translation. of the impulses through the receiving devices is also prevented.

The invention will be understood from the following description and by reference to the accompanying drawings in which Fig.

line and cooperates with Fig. l in the description of the invention. Fig. 3 is an "al-.. ternative arrangement of the receiving circuit shown in Fig. 2.

In Fig; 1, the rectangle designated by denotes the inward equipment at station A and corresponds to the inward equipment at B' which is included within the broken lines Cl, D in Fig. 2. The smaller rectangles T designate telegraph equipment associated with the transmission line. 'In' Fig. 2, the line L represents any power equipment or transmission line in the neighborhood of the line P and may be considered a source of disturbance to this line. Assuming the operator at A is called upon? to send out a series of impulses from the 'dial 100 in order to seize the line switch associated with line relay 200, she inserts plug 101 into jack 102 and establishes a circuit extending from grounded battery 125, normal contacts of key 126, through the normal contacts of the circuit controlling elements 127 and 128 which are mounted on thearmatures of relays 123 and'12 l, respective-v, ly, the armature and lower contacts of relay 105, the winding of the lower coil of polar relay 105, conductors 106 and 107, sleeve contacts of plug 101 and jack 102, andthence to ground through the windings of relays 108 and 109. The. current-flowing from bate tery 125 to the lower contact of relay 105 shunts winding of relay 104:. This'permits a second eurrent'to be traced from grounded lay 108 is slow operating in'orderthat the.

line conductors of the line P may be connected to the 1700 cycle current source 110, before relay 108 operates. A pulse of current, theduration of which depends upon the time constants of the armatures of relays 108 and 109 is thereupon sent out over the line 1? by way of the arinatures and back over which relay 217 first operated.

contacts of relay 108, front contacts and armatures of relay 109, the line conductors of line P, armatures and back contacts of relays 201, 202 and 223, through the filter 203 and the primary winding of repeating coil 2041. The rectifier205 is so arranged as to rectify the alternating current ineuced, in the secondary winding of repeating coil 204, and to permit a unidirectional current to flow through the windings of relay 206 to effect itsoperation. Assuming the first half cycle of current to be in the direction indicated bythe arrow in the primary winding of repeating coil'204, there will be a half cycle of current'induced in the secondary winding in the opposite direction, as indicated by the arrow, which'current will traverse a path extending through the upper right-hand winding of repeating coil 20 1, conductor 207, winding of the upper coil of relay 208, the upper plate and filament o1": rectifier 205, and thence through the windings of relay 206. -The second half cycle finds a path through the lower right-hand winding of repeating coil 204, conductor 209, winding of the lower coil of relay 208, lower plate and filament of rectifier 205, and .thence through the windings of relay 206. Relay 208 is so designed that the time constant of its armature keeps :the moving, member normally associated therewith in engagement with the contacting element 210 during receptioneof alternating currents of the proper signaling frequencies.

Relay 206 operates and interrupts the normal energizing circuit for relay 211 which circuit may be traced from grounded battery, movable member of relay 208, contacting element 210, conductor 212, contacts of relay 206, conductor 213, and thence to ground through the winding of relay 211. Relay 211 in deenergizing retracts its armature and establishes a circuit extendingfroin grounded battery, right-hand winding of line relay 200,00I1duct0rs 21-1, 215 and 216, winding ofsslow-release relay 217, armature and backcontact of slow-to-operate and torelease relay 218, conductor 219, back contact and armaturenof relay 211, windings of relay 220, conductors 221 and 922 to ground ALIA-I through the left-hand winding of line relay 200. Upon response of relay 217, due to thls circuit, its inner armature and front contact prepare acircuit for the front contact of relay 211 while the left-hand arma-- ture applies ground to energize relay 218. The response of relay 218 disconnects the circuit for the back contact of relay 211 The contacts of the relay 211 are preferably of the make-before-break type, so that when relay 206 restores upon cessation of the impulse of alternating current and relay 211 reoperates, it continues atits armature and front contact, the circuit through relays tureand back contact of relay 115.

- dial 100.

200, .217 and 220. That is, relay .217 although quick to operate is slow to release. thereby retaining the circuit to the front contact of relay 211 during the movement of'the armature of relay 211, and the slow operating feature of relay 218 serves'to delay the interruption of the original energizing circuit through relay 217 sufficiently to ermit this relay to remain operated.

When the line switch associated with line relay 200 is seized, a signal is transmitted back from the equipment at B to notifythe operator that she may proceed to dial. The transmission of such a signal is disclosed in a patentof H. W. ONeill, No. 1,579,236, issued April 6,1920. The alternating current flowing from the selector in sending back a signal flows over the line conductors 235 and 236, back contacts and armatures of relays 223, 202 and 201, armatures and front contacts of relays 109 and 108, tip and ring contacts of jack 102 and plug 101, the outer z'ontacts of key 111 (assuming this keyto have been operated), conductors 120 and 110, conductors 117 and 118, the armatures and back contacts of relay 112, through the primary winding of the universal transformer 130. A current is thereupon'induced in the secondary windings of transformer 130 of a frequency similar to that incoming over the line and is rectified by the rectifier 131 and flows as a unidirectional current through the windings of relay 132. The rectifier 131 operates in a manner similar to that described in connection with the rectifier 205.

Relay 132 isthereupon operated and establishes a circuit extending from grounded battery, through the armature and front contact of relay 132, winding of relay'133, conductor 134, through the lower normal contacts of the dial 100, conductor 11 1, and thence to ground, through the outer arma- Relay 133'is energizedin the circuit just traced. Upon'cessation of the incoming alternating current, relay 132 becomes deenergized but relay 133 being slow to release establishes a circuit extending from grounded battery, armature and lower contacts of relay 132, conduct-or 135, lamp 180, the armature and front contact of relay 133, and thence to ground at the outer armature and back contactof relay 115 over the energizing circuit previously traced for relay 133.

Upon noting the illumination of lamp 180, the operator at'A proceeds to operate the The structure and operation of such dials are well known in the art and a brief description of their application to the system in question will suiiice to complete the description of the circuit disclosed. When the dial is operated, the transfer con tacts of the dial disconnect relay 133 to extinguish lamp 180 and establish a circuit extending from grounded battery, the upper cont-acts of this dial, which shunt the winding of relay 112, through the resistance element 113, loweralternate contacts of the dial- 100, conductor 114, and thence to ground over the back contact and outer armature of relay 115. Upon release of the dialing mechanism, the upper contacts are intermittently separated in accordance with the setting of the dial so that the shunt around relay 112 is removed a corresponding number of times. By the intermittent operation of relay 112, the 1700-cycle source 116 is alternately connected to and disconnected from the armatures of relay 112, whereupon current pulses from the source 116 are sent out over conductors 117' and 118, 119 and 120, outer contacts of key 111, tip and ring contacts of plug-101 and jack 102, front contacts and armatures of relays 108 and 109, line conductors of the line P,

armatures and back contacts of relays 201, 202 and 223, through the filter amplifier 203 and the primary winding of repeating coil 204. As described in connection with the current impulse sent outfrom the source 110, current pulses are induced in the secondary winding of repeating coil 20 1 and passed through the windings of relay 208, rectifier 205 and the windings of relay 206, whereupon the latter relay is operated in accordance with the impulses.

Each time relay 206 operates, the normal energizing circuit for relay 211 is interrupted, whichrelay in turn intermittently iuterrupts'through its armature and front contact an energizing circuit for line relay 200 of the switch. The slow release nature of relay 217 prevents the disconnection of the circuit at :its inner front contact. Line relay 200 follows the intermittent operation of relay 211 and causes its; associated switching apparatus to experience a movement to effect the desired connection.

It will now be assumed that the called subscriber has been signaled over the completed connection, and responds by the removal ofthe receiver from the switchhoolr. In removing the receiver from the switchhook, battery across the line conductors is reversec in a manner well known in the art whereupon the polar relay 220, which is bridged across the line through the armature and front contact of relay 211, front contact and inner armature relay 217, winding of relay 217 and conduct r 216, operates. Relay 220 in operating establishes a circuit eXtend-' ing from grounded battery, its armature and lower contact, conductors 225 and 226, lower contact of relay 227, conductor 228 to ground through the winding of relay 202. Relay 202 operates in this circuit and at its upper and middle armatures and front con t-acts simultaneously applies 900 and 1700 cycle currents from the sources 229 and 230 respectively, to the line conductors of line P. The currents from the sources 229 and 230 flow out over the front contacts and armatures of relay 202, back contacts and armatures of relay 201, line conductors of line P, armatures and front contacts of relays 109v and 108, tip and ring contacts of jack 102 and plug 101, normal contacts of key 111 (the key 111 having been returned to normal after dialing) conductors 121 and 122, and thence through. the windings of relays 123 and 124. Relays 123 and 124: are respectively responsive to currents of 1700 and 900 cycle. frequencies. Relay 202 also establishes an energizing. circuit for relay 227 which-maybe traced from grounded battery, armature and lower contacts of relay 220,

conductor 225, lower winding of relay 227, conductor 273, to ground through the front contact and armature of relay 202. Relay. 227 is of the polar type and the direction of current flowing in its lower winding causes its armature to be moved from its lower to its upper contact, thereby interrupting the circuit of relay 202. This relayin restoringdisconnects sources 229 and 230.

Relays 123 and 12 i operate simultaneously in the circuit previously traced'and at their respective circuit controlling elements 127 and 128, disconnect the battery 125 from the winding of the lower coil of relay 105;

This permits the current in the winding of relay 103 and the upper coil of relay105'to move the armature of the latter relay from its lower to its upper contact stop. On ces battery 125 shunts the winding of relay 103 the restoration of which extinguishes la1np 129 and connects battery 140 through the wlndlng of relay 104 and the lower winding of relay 105 to the conductor 106. The

response of relay 104: disconnects relay 103 to prevent premature response of the latter relay upon the receipt of the next impulse of alternating current to disconnect battery 125. In the present condition of the circuit the greater strength of current through the upper winding of relay 105 insures that such relay will maintain its armature in e .gagemerit with its upper contact.

Assuming the period of conversation to have ended, the called subscriber replaces his receiver on the switclihool: and, in so doing, v

again reverses the battery across the line conductors, whereupon relay i220 separates its lower and closes its upper contacts thererelay 202.

by applying current from grounded battery over conductor 2 10, upper contacts and armature of relay 227, conductor 228 and thence to ground through the winding of Relay 202 thereupon operates andv at its upper and middle armatures and front contacts again connects the current and to the line conductors of line 1?. At its lowermost armature, relay 202 now establisl es a circ it including the upper winding relay conductor 2%, upper contacts of relay 220 to grounded battery at the armature oi the latter relay. The direction of current through the upper winding of relay 22l'causes such relay to move its armature from its upper to its lower contact stop. This deenergizes relay 202to disconnectcurrents and 230.

During the period in which the current sources 229 and 230 were connected to the line conductors of line Y relays 123 and 12 1 Were actuated, as described previously and effected the illumination of supervisory lamp 129 to notify the operator that she may proceed to take down the connection, and restore the apparatus to normal condition. In this instance the removal of battery from the upper contact 01 relay 105 permits the current in the lower winding of such relay to move its armature to its lower contact. On restoration of relays and 124 the battery 125 will shunt relay 10 1 and the restoration of relay 104 permits relay 103 to respond in series with the upper winding of relay 105 to disconnectrelay 10 1 and illuminate lamp 129. r

Removal of plug 101 from jack 102 results in the imn'iediaterelease of relay 108 to apply current from source 110 by way or" the front contacts of relay 100 (still in its operated condition due to its slow-to-release characteristics). In response to this impulse of current relay 206 disconnects the relay 211 which opens the direct current loop circuit i'or relay 200 for an interval sufiicient in duration to permit the release of relay 217 and also the release of the relays in the switches not shown, wiereby the switches are restored to normal. Following the release of relay 217 and the disconnection of the slow-to-releasc relay 218 cessation of the alternating current impulse permits relay 206 to restore and operate relay 211, in advance or" the instant when the normal con- 'tacts of relay 218 may establish the circuit affects the transmission line P and induces currents in the secondary windingof repeating coil 204, which currents pass through the winding of relay 208m a manner previously described. "When such currents are of anature which will pass through the filter 203 and be rectified by the device 205 a bias ot polarrelay'128 in one direction or an other may be established. Relay 208 being designed to maintain its armature in normal condition only upon the application of rela tively high freouency cu rents to its windings, is .aiiected in such a manner by these currents as to cause its armature to operate in one direction or the other depending on which polarity predominates. Assuming the ,urge predominating to be of such polarity U to cause the armature member of relay to come into engagement with the lower t associated with the conductor 2 11, a

' is established from grounded battery,

ll'Clllt armature and lower contact 242 of relay 208, conductor 2451, and thence to ground through the winding of relay 223. Relay 223 thereupon operates and at its an iatures and front con-acts connects the 1300 cycle current source 24-3 to the line conductors of the line Current from this source fiows over the armatures and front contacts of relay 223, back contacts and armatures of relays 202 and 201, armatures and trout contacts of relays 109 and 108, tip and ring contacts of jack 102 and plug 101, conductors 119 and 120, and 146, the filter amplifier 14?, and the primary winding of transformer 14:8. The currents induced in the secondary windings of transformer 1l-8are rectified by the rectifier 149 and pass through the windings of relay 150, whereupon a circuit is established which may be traced from batteries 125 and 1 10, as previously traced, to conductor 106, winding of relay 115, and thenceto ground through the contacts and armature of relay 150. Relay 115 thereupon energizes and establishes an obvious circuit for lamp 151 and at its inner armature and front contact completes a self-locking circuit. The operation of relay 115 also disables the dial 100 by disconnecting the ground already traced.

On noting the illumination of lamp 151, the operator is informed of the unstandard condition of the line and immediately with draws plug 101 from jack 102, and in order to render the dial operative and to extinguish the lamp 151, it is necessary that plug 101 be momentarily inserted in jack 160. Upon the insertion or plug 101 into iacl: 160, ground is placed. on the sleeve conductor 107 of the cord circuit, thereby shunting relay 115 to extinguish the lamp 151 and to again connect ground to the dial 100. This disconnection will permit the complete restoration to normal of relays 108 and 109 in order that an impulse of alternating cur-V the same rent may be transmitted over the line to effect release of the distant switches as already described. The operator may then withdraw plug 101 from jack 160 and again inserts it into jack 102 and'proceedto redial. i

The'jack 375 is employed in establishing a call origii'iating at station E andthe relays 376 and 201 correspond to and function in a manner similar to relays 108 and 109, re

spectively. When the line P is in use from the point A, a busy condition may be established at this jack 375 in. the same manner as that employed in the copending application of ONeill, Serial N 0. 586,616, filed September C 192 i The arrangement shown in Fig. 3 provides a normally balanced circuit adapted to be non-responsive to every other half cycle of incoming current and to utilize only half cycles of the same polarity to operat the associated switching apparatus.

The direction of the effective half cycles of current is indicated on the drawing by the arrows and the current inducedin the upper winding of the secondary of repeating coil 304 traverses a path through the upper right-hand winding of coil 304, upper coil of relay 306, plate'a-nd filament of rectifier 301, upper coil of relay-308, conductor 317 and back through the upper winding of the secondary of repeating coil 304. The current induced by half waves in the lower secondary winding of repeating coil 304 flows from the mid-point of the secondary winding through the lower coil thereof, conductor 309, lower coil of relay 308, the plate and filament of rectifier 305, the lower winding of relay 306 and back to the mid-point of the secondary winding of repeating coil 30%. The windings of relay 308 are so proportioned and the lower winding thereof resonated by the'condenser 302 that under the regular operating frequency of the line, relay 306 does not operate whereas relay 308 does operate and interrupts the normal energizing circuit for relay 311. The dissimilar windings of relay 308, due to condenser 302, present like impedances with respect to the differential paths through relay 306 at the frequency employed for dialing. event that currents of a difierent frequency reach the circuits of relays 306 and 308, a non-symmetrical impedance condition will result in the response of relay 306 to engage its contacts. Before the break signal relay 223 may be operated, however, it is necessary for line relay 308 to also be operated in order that grounded battery may be supplied through the contacts of relay 306. The circuit for relay 311 may be traced from grounded battery through the armature and lower contact of relay 308 and conductor 313 to ground through the repeating In the winding of relay 311. Relay 311 functions 1n a manner similarto that of relay 211- de'-' 7 scribed in connection with Fig. 2. r

If in establishing a connection the distant switches encounter a trunk or line" busy condition, alternating"-currents may be transmitted back over the line and the dialing signal lamp 180 or the supervisory lamp 129 illuminated,

, depending upon the position of key 111. 1 i Signal 180is'adapted to respond whena paths busy or a line busy,condition is encountered by the distant switching devices during tion. Impulses then be sent same manner as is employed in the copending application of ONeill, Serial No. 586, 616, filed September-'7, 1922." A first response of the relay 1 32 serves to energize relay 133, and subsequent incoming impulses in operating relay 132 will cause the lamp 180-to be flashed in one characteristic manner for paths'busy condition and in another characteristic manner for a line busy condition, as is well understood in the art. Y 7 In case busy signals are returned subse quent to the restoring of key 111", the supervisory lamp 129 will be correspondingly operated. The key 126 is for the purpose of permitting the operator to reverse any given condition of the lamp 129. If the lamp is lighted, momentary operation of the key will cause it to be extinguished and if the lamp is extinguished, momentary operation of the key will cause it to be lighted. V 7

Further supervisory service may be ren- 'dered by the signal 180, for example, in the event that dialing key 111 isnot'restored suflicien'tly soon after the completion of dialing operation. The response of 2. called .the establishing of a, connecof alternating current may back over the toll line in the that the called'subscriber resorts to flashing, that is, moves his switchhook to call the operator, the resulting impulses of alternating current will cause lamp 180 to be extinguished each time the ,relay 132 responds and lighted each time it is released.

What is claimed is:

1. In a switching system, a line, means for transmitting high frequency alternating current impulses, a signal, and means for operating said signal actuated during the transmission of said impulses upon the establishment of electrical conditions on the line other than said impulses.

2. In a switching system, a line, means for transmitting high frequency alternating current impulses, a signal, and means for operatingsaid signal and disabling the transmitting means actuated during the transmission of said impulses upon the es ing current impulses over said line, means responsive to saidimpulses for translating the same into direct current impulses for switching purposes, a signal, and means operative to actuate said signal uponthe establishment of electrical conditions onthe line otherthan said impulses. 4. "In a switching system, a line, means for transmitting high frequency current impulses over said line, means responsive to saidimpulses for translating the same'into direct current impulses for switching purposes, a signal, means operative uponthe establishmentof electrical conditions other than said, alternating current impulses to disable the impulse responsive means, and means operative to actuate said signal .when said impulse responsive means is disabled. 5. In a switching system, a line, means for transmitting frequency current impulses over said line, means responsive to said impulses fortranslating the same into direct current impulses for switching purposes, a signal associated with said line, a source of high frequencyalternating, current, means for disabling the impulse responsive means operative upon the establishment of any electrical conditions on the line other than the impulse produced by the transmittitng means, means for connecting said source of high frequency alternating current to the line operative when the impulse responsive means is disabled, and means responsive to current from said source when connected to the line for operating said signal.

6. In a signaling system, a transmitting medium, means for transmitting high frequency alternating currents over said'medium, switching means responsive to currents other than said high frequency currents present on said transmitting medium for disabling said transmitting means.

7. In a signaling system, a transmitting medium, means for. transmitting high frequency alternating currents over said medium, a signal, switching means responsive to currents other than said high frequency,

alternating currents present on said transmission medium for disabling, said transmitting means and for operating said signal. In witness whereof, I hereunto, subscribe myname this 17th day of NoveinbersA. D. 1922.

HENRY wonnnin 

